Broadcast or uni-directional distribution systems, such as digital direct broadcast satellite (DBS) or some digital cable systems, have demonstrated the capability for highly reliable delivery of digital media. Typically in these systems the various components of a program such as the video, audio, closed captioning, and electronic program guide (EPG) are transmitted in real time as logical streams of data packets that are decoded by a set-top box and then “presented” to a viewer on a television display. If there is a substantial impairment in the real-time delivery, such as that caused by a rain outage, the viewer is well aware of the cause and, to some extent, appreciates the reason for the impairment.
The deployment of digital video recorders (DVRs) in satellite and cable systems provides the opportunity for non-real-time content delivery. In non-real-time content delivery, the content can be stored on the DVR and played back at a later time. During playback the customer may take the viewpoint that since it is not raining during playback, the displayed content should have no impairments. Furthermore, systems such as DBS and cable have a need to compete with content playback from digital video devices, such as DVD's, that provide a near flawless playback experience.
Given the factors above, there is a need to provide delivery without significant impairment and the need to know at the receiver, with high certainty, that reliable delivery has occurred at the receiving end.